Cooler comprising sloping grate sections



COOLER COMPRISING SLOPING GRATE SECTIONS Filed Jan. 17, 1966 & k

INVENTOR eilwm mwrm ATTORNEYS United States Patent 3,412,477 COOLER COMPRISING SLOPING GRATE SECTIONS Karl-Heinz Kayatz, Hamburg-Nienstedten, Germany, assignor to Fuller Company, Catasauqua, Pa., a corporation of Delaware Filed Jan. 17, 1966, Ser. No. 521,170 Claims priority, application Germany, Jan. 26, 1965, P 35,948 3 Claims. (Cl. 34-164) ABSTRACT OF THE DISCLOSURE A heat exchanger composed of two grate sections. The first grate section slopes downwardly towards the second grate section which, itself, slopes upwardly.

The present invention relates to the cooling of materials such as cement clinker, sintered ores, calcined phosphate, or the like, and is concerned more particularly with the cooling of such materials by means of grate coolers.

Grate coolers for these materials have been used which include plural grate sections, variable materialbed depths and variable conveying velocities. These have been arranged so that the first grate section has a lower conveying velocity than the following section, while this first section can be arranged on a downward slope and the second or last section can be arranged horizontally.

The structures of such coolers are typified by US. Patent 2,137,158, issued Nov. 15, 1938, to A. E. Douglass and US. Patent 2,846,778 issued Aug. 12, 1958, to Harry A. Markle, Jr.

The purpose of this arrangement is that, on the sloping and slowly moving grate section, a heavy layer of cooling material is accumulated, so that a better heat exchange and a higher heat recuperation is achieved. Meanwhile, on the subsequent, horizontal grate section with the higher conveying speed, a normal layer of cooling material of about 200 to 250 mm. follows.

In practice however, particle sizings of materials have been encountered such that material in the heavy bed layer, on the sloping grate section, will flush or flood forward onto the horizontal grate section before the desired degree of cooling has been reached. Therefore, the desired retention of the heavy first-grate layer is prevented. This obviously will upset the thermodynamic balance of the entire system for which the first-section heat is to be recuperated.

In contrast, the present invention provides for arranging the second grate section on an upward slope. In this manner, the retaining of material on the first grate section is augmented so that the desired bed depth is achieved.

An additional advantage is achieved in that the discharge point for the cooled material from the second grate section lies at a higher elevation, so that further lifting of the material to facilitate subsequent conveying or handling is no longer necessary.

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3,412,477 Patented Nov. 26, 1968 Brief description of the drawings FIG. 1 is a side elevated sectional view illustrating llht invention.

A better understanding of the invention may bl derived from the following description and the accom panying schematic drawing. In the drawing, there is il lustrated a heat exchanger or cooler 5 which comprise; a first grate section 1 consisting of a plurality of alter nating stationary grates 6 and reciprocating grates 7 driven by a variable speed drive means 8. The grate sec tion 1 slopes downwardly toward a second grate sectior 2 which consists of a traveling endless conveyor sup ported and rotated about sprockets 9. The sprockets arc driven by a variable speed drive means 10. The first grate section 1 carries a heavy layer H of cooling materia thereon. The second grate section 2 carries a lightei layer L of cooling material, and is sloped upwardly tc restrain flooding from the first layer H.

Material to be cooled is supplied from a material source, such as a rotary kiln, to the first section at point 3, while cooled material is discharged from the second section at point 4 through a suitable discharge chute 11. The cooling is accomplished by cooling gases which discharge from conduits 12 that communicate with blower: 13, the gasses thereby traverse the grate sections it known fashion.

The heat exchanger is also provided with a gas discharge conduit 14 for discharging gasses from the heat exchanger. It is, however, appreciated that a portion 01 the gasses passing through the first grate section 1 may be exhausted back through the material supply point 3.

The present invention is an improvement in the invention set forth in German published application (DAS) No. 1,170,307 which discloses the advantages of differential bed thickness, and the employment of differential conveying velocities in the grate sections to accomplish the differing bed thicknesses.

I claim:

1. A heat exchanger comprising first and second grate sections, means for varying the conveying speeds of the grate sections to retain a relatively deep layer of cooling material on the first grate section and a thinner layer on the second grate section, said first grate section being arranged to slope downwardly toward the second grate section, and said second grate section being arranged to slope upwardly from the first grate section.

2. A heat exchanger as set forth in claim 1 in which the second grate section comprises a traveling grate.

3. A cooler for cement clinker or the like which comprises a reciprocating-grate section sloped downwardly in its conveying direction, a travelling-grate section adjacent the discharge end of the reciprocating-grate section and sloped upwardly in its conveying direction, means for varying the conveying speeds of the grate sections, and means for traversing the grate sections and their overlying bed layers with a cooling gas.

References Cited UNITED STATES PATENTS 1,077,162 10/ 1913 Rodakowski 198-76 1,175,190 3/1916 Stuart 198-76 1,325,704 12/1919 Scott 198-76 2,137,158 11/1938 Douglass 263-32 2,362,677 11/ 1944 Stephens 198-76 2,598,931 6/1952 Narsted 34-233 2,846,778 8/1958 Markle 34-164 3,089,688 5/1963 Ostberg 263-32 FREDERICK L. MATTESON, JR., Primary Examiner.

A. D. HERRMANN, Assistant Examiner. 

